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One of the exciting developments in contemporary luminescence research is the development of rare earth triggered luminescent glasses, which are a type of lanthanide activated luminous material. For the first time, Ce3+, Eu3+ activated/co-activated Mg21Ca4Na4(PO4)18 orthophosphate glasses have been synthesized using the proposed work's melt quenching technique. The proposed glass sample's XRD pattern has an amorphous character, although its most prominent peak matches data from the Mg21Ca4Na4(PO4)18 standard ICSD database. FT-IR analysis was used to analyze the proposed glass sample's vibrational characteristics. Co-activated Mg21Ca4Na4(PO4)18 glass exhibits large emission peaks under UV excitations that cover the far red area during a photoluminescence examination. These outcomes demonstrate the proposed sample's value in applications such as WLEDs and plant cultivation.
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Phosphites are being recognized as the new emerging candidates for luminescence in the modern era. In the proposed research article, Ce3+/Eu2+ co-activated NaBa(PO3)3 phosphite phosphors synthesized utilizing sol-gel technique. Through the use of XRD and Rietveld refinement, the phase identity and crystal structure of produced phosphor are examined. SEM is employed to analyze the morphology and elemental composition of the prepared sample. The sample shows blue emission enhancement in the phosphor on energy transfer with the Ce3+ ion by 6 times. This highly instance blue emitting phosphor has color purity of 98.49%. These all results confirm that the prepared phosphor is potential candidate for WLEDs, display applications and blue emitting phosphor for plant cultivation applications.
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This article focuses on the effect of monovalent cation doping on the optical properties of rare earth (RE = Eu3+ , Tb3+ ) co-doped Ca14 Zn6 Al10 O35 which has been synthesized by a low temperature combustion method. Crystalline phase of the Ca14 Zn6 Al10 O35 phosphor was examined and confirmed by X-ray diffraction measurement. Under near-ultraviolet light excitation Eu3+ -doped Ca14 Zn6 Al10 O35 phosphor exhibit characterization of Eu3+ emission bands that are located at a maximum wavelength (λmax ) of approximately 470 nm and other peaks centred at 593 nm and 615 nm, respectively. With Tb3+ -doped Ca14 Zn6 Al10 O35 phosphor showing a green emission band centred at 544 nm under near-ultraviolet range. Furthermore, we studied the energy transfer process in Eu3+ /Tb3+ pair and enhancement in photoluminescence (PL) intensity with doping different charge compensation. Here we obtained the optimum PL emission intensity of the phosphor in broad and intense visible spectral range which may be significant for the fabrication of white light emitting diodes (WLEDs).
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Europio , Luminiscencia , Europio/química , Transferencia de Energía , Difracción de Rayos X , ZincRESUMEN
BACKGROUND: Metformin, by reducing intracellular Mycobacterium tuberculosis growth, can be considered an adjunctive therapy to anti-tuberculosis treatment (ATT). We determined whether metformin with standard ATT reduces time to sputum culture conversion and tissue inflammation in adults with pulmonary tuberculosis (PTB). METHODS: In a randomized, 8-week, clinical trial, newly diagnosed, culture-positive PTB patients were randomized to standard ATT (HREZ = control arm) or standard ATT plus daily 1000 mg metformin (MET-HREZ = Metformin with Rifampicin [METRIF] arm) for 8 weeks during 2018-2020 at 5 sites in India. The primary end point was time to sputum culture conversion by liquid culture during 8 weeks of ATT. Plasma inflammatory markers were estimated in a subset. A Cox proportional hazard model was used to estimate time and predictors of culture conversion. RESULTS: Of the 322 patients randomized, 239 (74%) were male, and 212 (66%) had bilateral disease on chest radiograph with 54 (18%) showing cavitation. The median time to sputum culture conversion by liquid culture was 42 days in the METRIF arm and 41 days in the control arm (hazard ratio, 0.8; 95% confidence interval [CI], .624-1.019). After 8 weeks of ATT, cavitary lesions on X-ray (7, 5.3% vs 18, 12.9%; relative risk, 0.42; 95% CI, .18-.96; Pâ =â .041) and inflammatory markers were significantly lower in the METRIF arm. Higher body mass index and lower sputum smear grading were associated with faster sputum culture conversion. CONCLUSIONS: The addition of metformin to standard ATT did not hasten sputum culture conversion but diminished excess inflammation, thus reducing lung tissue damage as seen by faster clearance on X-ray and reduced inflammatory markers. CLINICAL TRIALS REGISTRATION: Clinical Trial Registry of India (CTRI/2018/01/011176).
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Metformina , Mycobacterium tuberculosis , Tuberculosis Pulmonar , Adulto , Antituberculosos/uso terapéutico , Femenino , Humanos , Inflamación/complicaciones , Masculino , Metformina/uso terapéutico , Esputo/microbiología , Tuberculosis Pulmonar/diagnósticoRESUMEN
Aluminate-based phosphors have been the most investigated luminescent phosphors over decades due to their outstanding optical properties. In the proposed work, a series of Sm3+ -doped Ca8.25 Na1.5 Al6 O18 (CNAO) phosphor sample was prepared using a simple combustion technique with the help of two fuels i.e., urea-glycine. The purity of phase and structural analysis of the CNAO phosphors were confirmed using X-ray diffraction analysis. Vibrational features of this phosphors confirmed were via Fourier transform infrared analysis. A photoluminescence study of this phosphor showed a doublet emission at 568 and 576 nm in the yellow region attributable to the 4 G5/2 â6 H5/2 transition of Sm3+ ions, whereas a doublet peak noticed in red region ranged from 600 to 620 nm and was attributable to the 4 G5/2 â6 H7/2 transition of Sm3+ ions. Moreover, Commission Internationale de l'éclairage colour coordinates were also located in the yellowish-red region and confirmed the potential of this phosphor as a yellowish-red component for white light-emitting diodes and display devices applications.
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Borochlorate phosphors have shown their worth in modern day lighting over the last few years. Colour tunability of the phosphor is a modern techniques used to obtain white-light-emitting diodes (WLEDs). In the proposed work, Sm3+ ,Eu2+ -activated/co-activated Ba2 AlB4 O7 Cl phosphors were investigated for WLED applications as well as display devices. A convectional solid-state diffusion method was used to synthesize the proposed phosphors. X-ray diffraction (XRD) of the proposed phosphors confirmed the crystalline nature of the sample. Morphological studies on the samples were carried out using scanning electron microscopy analysis. A photoluminescence study of the colour tunable phosphor showed the characteristic peak of Sm3+ together with one broad peak for Eu2+ ions. Red to blue colour tunability was observed in the proposed phosphor with enhancement of Eu2+ ions. All these results showed the worth of this sample in WLED applications as well as in display devices.
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Europio , Luminiscencia , Europio/química , Difracción de Rayos X , Microscopía Electrónica de Rastreo , IluminaciónRESUMEN
Pyrochlore phosphors have shown their worth in modern day lighting in the last few years. Colour tunability of the phosphor is one of the modern techniques used to obtain white light-emitting diodes (WLEDs). In the proposed work, Y2 Zr2 O7 :Sm3+ ,Eu3+ phosphors were investigated for WLED applications as well as display devices. A convectional solid-state diffusion method was used to synthesize the proposed phosphors. X-ray diffraction of the proposed phosphors was performed and compared with the standard Inorganic Crystal Structure Database. The crystal structure of the sample was cubic in nature, obtained from Rietveld refinement. Vibrational and morphological studies on the samples were carried out using Fourier transform infrared spectroscopy and scanning electron microscopy analysis. The photoluminescence study of the colour tunable phosphor showed the characteristic peak of Sm3+ together with the two sharp peaks of Eu3+ ions. Greenish yellow to red colour tunability was observed in the proposed phosphor with enhancement of Eu3+ ions. All these results showed the worth of this sample for WLEDs applications as well as in display devices.
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In this work, RE3+ (Eu, Ce and Sm)-activated Ca10 (PO4 )6 F2 (fluorapatite) phosphors were synthesized by doping with different apatite minerals (SO4 , VO4, WO4 ) using a solid-state diffusion method. Optical and structural characterizations were performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and photoluminescence (PL) spectroscopy. XRD characterization showed the crystalline nature of the phosphor. PL properties were investigated under ultraviolet light excitation for all three rare earths. CIE chromaticity revealed the colour emitted in the visible region. Luminescence intensity was enhanced considerably by tuning the host matrices after core-shell formation by substitution with other ions producing promising candidates for white light-emitting diode materials.
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Doping en los Deportes , Sustancias Luminiscentes , Europio , Luminiscencia , MineralesRESUMEN
Mineral fluorite or fluorspar (CaF2 ) can host significant quantities of trivalent REE3+ (rare earth element) by substitution with divalent Ca2+ . The fluorites associated with carbonatites are often REE-rich compared to those derived from sedimentary, hydrothermal, or Mississippi Valley-type (MVT) fluorites. The naturally occurring fluorites have several industrial applications one of which is for luminescence. Whether or not REE enriched, the fluorite makes an ideal host for REEs, which are very important phosphors. The naturally occurring fluorites are available in sufficient quantities to cater to the industrial demand. Investigations have been carried out on the fluorites from active fluorite mines at Dongargaon in central India. Thermoluminescence behavior of a natural fluorite sample was investigated using a Nucleonix TL 1009I thermoluminescence reader. Multiple traps formed in the broad thermoluminescent (TL) glow curve were found by TL anal deconvolution software. Trapping parameters for all multiple traps formed on deconvoluting broad TL glow curve were found by different methods like Initial rise method, Chen's Peak shape method and Ilich method.
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Luminiscencia , Mediciones Luminiscentes , India , Dosimetría Termoluminiscente , Difracción de Rayos XRESUMEN
Dosimetry is a technique that quantitatively measures the ionizing radiation absorbed by matter. The present study was conducted on the barites from a mine at Dongargaon in Central India. Morphological and structural analysis of proposed sample was carried out using X-ray diffraction and standard error of the mean. Thermal analysis and chemical composition of the proposed sample were carried out using thermogravimetric analysis and differential thermal analysis, and electron probe microanalysis. Thermoluminescence (TL) studies on a natural barite sample were performed using a Nucleonix TL1009I TL reader following sample irradiation with γ-rays generated from a 60 Co irradiation source. A broad TL glow curve was observed after TL study that was then deconvoluted using TLanal deconvolution software. Trapping parameters from the sample such as activation energy (E), order of kinetics (b), and frequency factor (s) were calculated using Chen's peak shape method, the initial rise method, and Ilich's method. The results indicated that the natural barite sample could be used in high-dose TL dosimetric applications in various fields.
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Sulfato de Bario , Mediciones Luminiscentes , Rayos gamma , India , Dosimetría Termoluminiscente , Difracción de Rayos XRESUMEN
Nipah virus (NiV) outbreak occurred in Kozhikode district, Kerala, India in 2018 with a case fatality rate of 91% (21/23). In 2019, a single case with full recovery occurred in Ernakulam district. We described the response and control measures by the Indian Council of Medical Research and Kerala State Government for the 2019 NiV outbreak. The establishment of Point of Care assays and monoclonal antibodies administration facility for early diagnosis, response and treatment, intensified contact tracing activities, bio-risk management and hospital infection control training of healthcare workers contributed to effective control and containment of NiV outbreak in Ernakulam.
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Control de Enfermedades Transmisibles/organización & administración , Urgencias Médicas , Infecciones por Henipavirus/epidemiología , Infecciones por Henipavirus/prevención & control , Virus Nipah , Salud Pública , Restos Mortales , Brotes de Enfermedades , Humanos , India/epidemiología , Eliminación de Residuos Sanitarios , Equipo de Protección PersonalRESUMEN
PURPOSE: The purpose of the study was to propose a method of prone positioning for posterior cervico-dorsal spine surgeries that is easy to achieve without additional equipment and may reduce complications associated with prone positioning in patients. METHODS: 41 patients underwent posterior spine surgeries using our method of prone positioning on a fluoroscopy compatible conventional operation table, and the technical difficulties and complications associated were noted. After induction under general anaesthesia in supine position, cervical tongs were applied. An assembly of two adequately padded cylindrical bolsters and two lateral brace attachments was set on a conventional operating table. The patient was then positioned prone so that the tongs as well as insertion pins of the tongs rest on the lateral brace attachments, with the face and head suspended freely in between. A neutralisation weight was then applied suspended from the tongs to stabilize the head. RESULTS: The time required for patient positioning was noted and was found to be nearly the same as that required for traditional prone positioning. No problems were noted during patient positioning and with anaesthesia tubing management. All surgeries went well without position related complications except for one patient who developed post-operative macroglossia. All cervical tong pin sites healed without any complications. The fluoroscope easily gained access to the operative areas. CONCLUSIONS: Our modification appears simple, versatile and reproducible for posterior approach procedures of the cervical and upper dorsal spine in prone position. Also, the method can be easily implemented in most conventional operating room facilities with minimal surgeon effort and without the need for any additional inventory.
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Tirantes , Procedimientos Ortopédicos/instrumentación , Procedimientos Ortopédicos/métodos , Columna Vertebral/cirugía , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Posición Prona , Adulto JovenRESUMEN
Phosphites are the new emerging candidates in the field of luminescence in the modern era. In the present investigation, Tb3+/Eu3+ activated/co-activated LiAl(PO3)4 phosphor was prepared by a wet chemical method, and the effect of R+ (Na+, K+) ions on photoluminescence (PL) properties of these phosphors are investigated. Phase identification and crystal structure of the prepared phosphor were determined using XRD and Rietveld refinement, respectively. Morphological study and elemental analysis of the proposed phosphor with elemental analysis of the sample were performed using SEM and EDS. The PL properties of the proposed phosphor showed three simultaneous emission peaks in the visible range, giving color-tunable emission. The charge compensation of Na+ and K+ ions make a significant impact on the PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors. The PL intensity of Tb3+, Eu3+ co-activated LiAl(PO3)4 phosphors was significantly enhanced by factors 1.2 and 1.4 when Na+ and K+ charge compensators, respectively, were introduced. To manifest the charge compensation effect of alkali metals the optimum intense sample in the co-doped sample was used. These results indicate the potential candidacy of the studied phosphor for further improvement in PL properties for application in solid-state lighting.
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Giant cell tumor (GCT) or osteoclastoma is a benign, locally aggressive tumor with a tendency to recur. Involvement of the axial skeleton is very rare and majority of them are seen in the sacrum. The authors report a rare case of a 19-year-old female who presented with a C2 dens GCT with a pathological fracture and atlantoaxial dislocation. The patient was operated in two stages: first stage, with posterior instrumentation and stabilization followed by the second stage, tumor resection by anterior transoral approach. The residual tumor cavity was packed with autologous corticocancellous bone grafts. At a 5-year follow-up, computed tomography scan showed a C1-C2 fusion mass. There was no radiological or clinical evidence of tumor recurrence with the patient having good functional outcome without any neurological deficit.
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Giant cell tumor (GCT) or osteoclastoma is a benign, locally aggressive tumor with a tendency to recur. Giant cell tumors typically occur in the epiphysis of long bones, including the distal femur and proximal tibia. They are uncommonly found in the small bones of the foot or ankle, and involvement of talus is rare. The authors present a case of GCT of the talar body in a 21-year-old man, which was diagnosed radiologically by the presence of a well-defined osteolytic lesion involving more than half of the talar body with thinning of the cortices. An intralesional curettage and chemical cauterization with phenol was done using a medial approach following an osteotomy of the medial malleolus for adequate exposure. Intraoperative frozen section of curetted tissue was sent and was reported as benign GCT. The residual cavity was packed with autologous corticocancellous bone grafts fashioned in a T-construct like manner. A protective cast was applied for a period of 2 months and patient was subsequently gradually mobilized to full weightbearing status. At 2-year follow-up, there was no clinical or radiologically evident signs of recurrence. There was good consolidation of the bone graft in the talus with no signs of collapse of the weightbearing articular surface. LEVELS OF EVIDENCE: Therapeutic, Level IV: Case Study.
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Neoplasias Óseas/cirugía , Tumor Óseo de Células Gigantes/cirugía , Ilion/trasplante , Astrágalo/cirugía , Neoplasias Óseas/patología , Tumor Óseo de Células Gigantes/patología , Humanos , Masculino , Astrágalo/patología , Trasplante Autólogo/métodos , Adulto JovenRESUMEN
OBJECTIVE The authors' aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities. METHODS The authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (< 6 levels). Preoperative and postoperative standing radiographs were evaluated to measure segmental lordosis (SL) along with standard sagittal parameters. Radiographic signs of pseudarthrosis at previously fused levels were also sought in all patients. RESULTS The average patient age was 54 years (range 30-66 years). The mean follow-up was 11.5 months (range 5-26 months). The mean SL achieved with 12°, 20°, and 30° cages was 13.1°, 19°, and 22.4°, respectively. The increase in postoperative SL at the respective surgically treated levels for 12°, 20°, and 30° cages that were used to overpower posterior instrumentation/fusion averaged 6.1° (p < 0.05), 12.5° (p < 0.05), and 17.7° (p < 0.05), respectively. No statistically significant difference was found in SL correction at levels in patients who had pseudarthrosis (n = 18) versus those who did not (n = 18). The mean overall lumbar lordosis increased from 44.3° to 59.8° (p < 0.05). In the long-construct group, the mean improvement in sagittal vertical axis was 85.5 mm (range 19-249.3 mm, p < 0.05). Endplate impaction/collapse was noted in 3 of 36 levels (8.3%). The anterior complication rate was 13.3%. No neurological complications or vascular injuries were observed. CONCLUSIONS ALIF in which hyperlordotic cages are used to overpower posterior spinal instrumentation and fusion can be expected to produce an increase in SL of a magnitude that is roughly half of the in-built cage lordotic angle. This technique may be particularly suited for lordosis correction from the front at lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.
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Lordosis/cirugía , Vértebras Lumbares/cirugía , Región Lumbosacra/cirugía , Adulto , Anciano , Estudios de Factibilidad , Humanos , Persona de Mediana Edad , Complicaciones Posoperatorias/cirugía , Estudios Retrospectivos , Fusión Vertebral/métodos , Resultado del TratamientoRESUMEN
STUDY DESIGN: Technical report on cadavers. OBJECTIVE: To evaluate preliminary feasibility and safety of lumbar sagittal alignment correction with anterior hyperlordotic cages used to overpower previous posterior spinal instrumentation. METHODS: Hyperlordotic 30° anterior lumbar interbody fusion (ALIF) cages were inserted in collapsed L5-S1 disc space of 2 cadavers to overpower prior posterior L5-S1 pedicle screws and rod constructs. A distinct technique of opening up the disc space and creation of intersegmental lordosis was employed using a large endplate distractor and transforaminal lumbar interbody fusion (TLIF) paddle distractor. Assessment of increase in the intersegmental lordosis (ISL) was made using lateral fluoroscopic imaging. Postprocedural computed tomography (CT) scans were obtained to evaluate any failure of posterior instrumentation and to serve as a surrogate marker for bone quality. RESULTS: The 2 cadavers selected (from an available number of 10) were males: 82 and 84 years of age, respectively. Both had marked L5-S1 disc space collapse. The ISL achieved with hyperlordotic cages was 27.6° for the first cadaver (up from 4.9°) and 23.1° for the second one (up from 4.6°). No obvious screw-rod failure or cutout of instrumentation occurred. Postprocedure CT scans did not reveal any loosening of screws or cutout through endplates. Hounsfield unit values calculated on axial CT cuts were 73.50 (osteoporosis) and 80.70 (osteopenia) respectively for the 2 cadavers. CONCLUSION: Based on the results of the cadaveric experiment, overpowering of posterior instrumentation can be effectively achieved. Biomechanical and clinical studies are indicated to further evaluate the suitability and safety of this technique.
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OBJECTIVE The aim of this study was to evaluate the segmental correction obtained from 20° and 30° hyperlordotic cages (HLCs) used for anterior lumbar interbody fusion in staged anterior and posterior fusion in adults with degenerative spinal pathology and/or spinal deformities. METHODS The authors report a retrospective case series of 69 HLCs in 41 patients with adult degenerative spine disease and/or deformities who underwent staged anterior, followed by posterior, instrumentation and fusion. There were 29 females and 12 males with a mean age of 55 years (range 23-76 years). The average follow-up was 10 months (range 2-28 months). Radiographic measurements of segmental lordosis and standard sagittal parameters were obtained on pre- and postoperative radiographs. Implant subsidence was measured at the final postoperative follow-up. RESULTS For 30° HLCs, the mean segmental lordosis achieved was 29° (range 26°-34°), but in the presence of spondylolisthesis this was reduced to 19° (range 12°-21°) (p < 0.01). For 20° HLCs, the mean segmental lordosis achieved was 19° (range 16°-22°). The overall mean lumbar lordosis increased from 39° to 59° (p < 0.01). The mean sagittal vertical axis (SVA) reduced from 113 mm (range 38-320 mm) to 43 mm (range -13 to 112 mm). Six cages (9%) displayed a loss of segmental lordosis during follow-up. The mean loss of segmental lordosis was 4.5° (range 3°-10°). A total complication rate of 20% with a 4.1% transient neurological complication rate was observed. The mean blood loss per patient was 240 ml (range 50-900 ml). CONCLUSIONS HLCs provide a reliable and stable degree of segmental lordosis correction. A 30° HLC will produce correction of a similar magnitude to a pedicle subtraction osteotomy, but with a lower complication rate and less blood loss.
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Fijadores Internos , Vértebras Lumbares/cirugía , Fusión Vertebral/instrumentación , Fusión Vertebral/métodos , Adulto , Anciano , Pérdida de Sangre Quirúrgica , Femenino , Estudios de Seguimiento , Humanos , Fijadores Internos/efectos adversos , Vértebras Lumbares/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Estudios Retrospectivos , Fusión Vertebral/efectos adversos , Resultado del Tratamiento , Adulto JovenRESUMEN
STUDY DESIGN: A narrative review of literature. OBJECTIVE: This manuscript intends to provide a review of clinically relevant bone substitutes and bone expanders for spinal surgery in terms of efficacy and associated clinical outcomes, as reported in contemporary spine literature. SUMMARY OF BACKGROUND DATA: Ever since the introduction of allograft as a substitute for autologous bone in spinal surgery, a sea of literature has surfaced, evaluating both established and newly emerging fusion alternatives. An understanding of the available fusion options and an organized evidence-based approach to their use in spine surgery is essential for achieving optimal results. METHODS: A Medline search of English language literature published through March 2016 discussing bone graft substitutes and fusion extenders was performed. All clinical studies reporting radiological and/or patient outcomes following the use of bone substitutes were reviewed under the broad categories of Allografts, Demineralized Bone Matrices (DBM), Ceramics, Bone Morphogenic proteins (BMPs), Autologous growth factors (AGFs), Stem cell products and Synthetic Peptides. These were further grouped depending on their application in lumbar and cervical spine surgeries, deformity correction or other miscellaneous procedures viz. trauma, infection or tumors; wherever data was forthcoming. Studies in animal populations and experimental in vitro studies were excluded. Primary endpoints were radiological fusion rates and successful clinical outcomes. RESULTS: A total of 181 clinical studies were found suitable to be included in the review. More than a third of the published articles (62 studies, 34.25%) focused on BMP. Ceramics (40 studies) and Allografts (39 studies) were the other two highly published groups of bone substitutes. Highest radiographic fusion rates were observed with BMPs, followed by allograft and DBM. There were no significant differences in the reported clinical outcomes across all classes of bone substitutes. CONCLUSIONS: There is a clear publication bias in the literature, mostly favoring BMP. Based on the available data, BMP is however associated with the highest radiographic fusion rate. Allograft is also very well corroborated in the literature. The use of DBM as a bone expander to augment autograft is supported, especially in the lumbar spine. Ceramics are also utilized as bone graft extenders and results are generally supportive, although limited. The use of autologous growth factors is not substantiated at this time. Cell matrix or stem cell-based products and the synthetic peptides have inadequate data. More comparative studies are needed to evaluate the efficacy of bone graft substitutes overall.
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BACKGROUND CONTEXT: The anterior approach to the lumbar spine is increasingly used to accomplish various surgical procedures. However, the incidence and risk factors for complications associated with anterior lumbar spine surgery (ALS) have not been fully elucidated. PURPOSE: To identify and document types of complications and complication rates associated with ALS, determine risk factors for these events, and evaluate the effect of measures used to decrease complication rates. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic review of the English-language literature was conducted for articles published between January 1992 and December 2013. A MEDLINE search was conducted to identify articles reporting complications associated with ALS. For each complication, the data were combined using a generalized linear mixed model with a binomial probability distribution and a random effect based on the study. Predictors used were the type of procedure (open, minimally invasive, or laparoscopic), the approach used (transperitoneal vs. retroperitoneal), use of recombinant bone morphogenetic protein-2, use of preoperative computed tomography angiography (CTA), and the utilization of an access surgeon. Open surgery was used as a reference category. RESULTS: Seventy-six articles met final inclusion criteria and reported complication rates in 11,410 patients who underwent arthrodesis and/or arthroplasty via laparoscopic, mini-open, and open techniques. The overall complication rate was 14.1%, with intraoperative and postoperative complication rates of 9.1% and 5.2%, respectively. Only 3% of patients required reoperation or revision procedures. The most common complications reported were venous injury (3.2%), retrograde ejaculation (2.7%), neurologic injury (2%), prosthesis related (2%), postoperative ileus (1.4%), superficial infection (1%), and others (1.3%). Laparoscopic and transperitoneal procedures were associated with higher complication rates, whereas lower complication rates were observed in patients receiving mini-open techniques. Our analysis indicated that the use of recombinant bone morphogenetic protein-2 was associated with increased rates of retrograde ejaculation; however, there may be limitations in interpreting these data. Data regarding the use of preoperative CTA and an access surgeon were limited and demonstrated mixed benefit. CONCLUSIONS: Overall complication rates with ALS are relatively low, with the most common complications occurring at a rate of 1% to 3%. Complication rates are related to surgical technique, approach, and implant characteristics. Further randomized controlled trials are needed to validate the use of preventative measures including CTA and the use of an access surgeon.